Question: 9 pencils cost $10.62. Which equation would help determine the cost of 5 pencils?
Explanation: There are several equations that could help determine the cost, each with a slightly different approach. If we let $x$ represent the cost of 5 pencils, we have the following proportion: $\dfrac{x}{5}$ We have to pay $10.62 for 9 pencils, and that can be written as a proportion: $\dfrac{\$10.62}{9}$ Since the price per pencil stays the same, these two proportions are equivalent. $\dfrac{x}{5} = \dfrac{\$10.62}{9}$